1. Field of the Invention
The present invention relates generally to a backup/recovery technique for a computer system, and more particularly to a backup/recovery system and method that securely backs up every type of data in a computer system according to the characteristic of such data.
2. Description of Prior Art
Conventional backup/recovery software establishes recovery points to backup data by using a static backup technique for storing data over a long period of time. When the data is in a state of maintenance, all valid data of such data in maintenance will be backed up. Accordingly to the conventional backup/recovery software, backing up data by this static backup technique takes up fixed storage space in the computer system. Moreover, the backed-up data is kept in a state of perpetuity, independent of other current or future data contained in a data storage means, such as a hard disk, of the computer system.
When executing the backup operation, the conventional backup/recovery software backs up all valid data in the data storage means by using the static backup technique and then keeps the backed-up data in a recovery point within a storage space. Ordinarily, the backed-up data occupies a large amount of storage space in the data storage means due to the great amount of valid data backed up. Moreover, the processing speed of the conventional backup/recovery software in backing up and/or recovering data is quite slow.
For example, the conventional backup/recovery software, such as the Ghost software developed by Symantec Corporation, includes a backup program to back up all data stored in selected partitions of the hard disk to a file. In addition, it further includes a recovery program for restoring the data from the file to the selected partitions of the hard disk. Prior to backing up the data, the Ghost software stops all other tasks in the computer. It then creates the backup file, with all the backed-up data, in a single task procedure. Generally, this backup procedure takes about 8 minutes per Gigabyte.
Since the Ghost software backs up all the valid data stored in the hard disk, the data itself backed up by the Ghost software occupies an extremely large space in the hard disk. In addition, all data currently used by the file system of the operating system (OS) will be backed up into the backup file. This occurs no matter whether such related data would be further changed in the future or not, thereby further occupying a great amount of space in the hard disk.
In a situation of independent operation from the current data of the hard disk, the conventional backup/recovery software can execute the restoration of previously backed up data in the hard disk. The conventional backup/recovery software nevertheless must back up the prior data in the hard disk. It is imperative that the prior data must be backed up fully beforehand. The conventional backup/recovery software with static backup technique, however, stores all the backed-up data in a region of the hard disk that other programs can have access also. This would likely induce the newly backed-up data to be destroyed. As a result, it would be almost impossible to restore the hard disk with such backed-up data for that has already been destroyed.
Current techniques available in the conventional backup/recovery software provide no notion of how to solve the problem of destroyed backed up data, not to mention the result of incapable reconstruction. In order to avoid destruction to the backed up data from taking place, users of the computer system will have to undertake some protective steps to carefully protect their backup data. Nevertheless, this would require very complex, yet probably questionable, procedures taken by the users. For instance, the users may store the backup data in a storage medium, such as backing up data to a CD-R disc. This, however, makes it very inconvenient to the users.
To save the storage space in the hard disk, some presently available backup/recovery software, such as the Goback software developed by Adaptec Corporation and the Pro Magic software developed by WASAY Incorporation, adopt a dynamic backup technique in establishing recovery points during the data backup process. Such dynamic backup technique restores the computer system to a previous state, in accordance with the previous backup data, from a current state. The valid data is backed up prior to making changes to the data. The backup file contains the backup data and identification information to identify the backup data. Such identification information is useful restoring the computer system in the future.
If there are not much change of the data, the data amount to be backed up will be relatively small. Accordingly, the storage space that will be occupied by the backup data can be reduced, and the required process time for restoration will also be short.
However, the dynamic backup technique has one major drawback. That is the restoration process of the dynamic backup technique depends on the current state of the data in the hard disk. For this reason, every change to the data has to be backed up by the conventional backup/recovery software.
But changes to the data in the hard disk usually grow in quantity as the time goes by. As such, the required recovery points and the valid data to be backed up will also increase. The increment of the size of the backup data gradually brings about a shortage of the storage space for storing data in the hard disk. Therefore, the computer system cannot keep all previously stored recovery points timelessly for the users. Some recovery points established previously will have to be deleted accordingly. It would be difficult for the users to attempt to keep a long-term certain state about the backup data.
In other words, the conventional backup/recovery software even though has the backup/recovery capabilities to back up and/or recover data in the hard disk, the amount of the data storage space required by the static backup technique is ordinarily larger than that is required by the dynamic backup technique. There are concerns about the data storage space consuming and time-consuming for the conventional backup/recovery software using static backup technique.
The dynamic backup technique used in the conventional backup/recovery software, on the other hand, often causes the problem of incapable of keeping earlier backup states permanently. Moreover, such conventional software intermingles previously stored recovery points needed to be preserved over a long period of time with the current data or any new recovery points just needed temporarily. Presently available backup/recovery software products either have the problems of being unable to keep the earlier stored recovery points permanently or have the problems of keeping the data states corresponding to the recovery points permanently, which indeed are needed only for a short period of time, thereby inducing the waste of data storage space and long consuming time during the backup and restoration.